NL2017586B1

Movatterモバイル変換

Info

Publication number: NL2017586B1
Application number: NL2017586A
Authority: NL
Inventors: Michael Halliday Andrew; Andrew Oliver Glen
Original assignee: Douwe Egberts Bv
Priority date: 2016-10-07
Filing date: 2016-10-07
Publication date: 2018-04-16
Also published as: MX2019003877A; BR112019006883A2; CA3039161A1; KR20190063464A; IL265884A; JP2019531135A; US20200047984A1; EP3523218A1; WO2018067011A1; WO2018067011A8; RU2019113353A; AU2017338600A1; CN109789968A

Abstract

In a capsule containing a substance constituted by a mass of loose, solid particles, for the preparation of a potable beverage by extracting and/or dissolving the substance by means of supplying a fluid under pressure into the capsule, a screen, permeable to water and impermeable to a predominant portion of particles of the substance is positioned between the substance and the bottom. The screen is provided with a plurality of passages dimensioned so that at least a fraction of the substance can pass through the passages in solid form. A beverage brewing system comprising such a capsule and a method of use of such a capsule are described as well.

Description

Translated fromDutch

OctrooicentrumPatent center

NederlandThe Netherlands

BI OCTROOI @ Int. CL:BI PATENT @ Int. CL:

B65D 85/804 (2016.01)B65D 85/804 (2016.01)

Aanvraag ingeschreven:Application registered:(73) Octrooihouder(s):(73) Patent holder (s):16/04/201816/04/2018Koninklijke Douwe Egberts B.V. te Utrecht.Koninklijke Douwe Egberts B.V. in Utrecht.(43) Aanvraag gepubliceerd:(43) Application published:--(72) Uitvinder(s):(72) Inventor (s):Andrew Michael Halliday te Utrecht.Andrew Michael Halliday in Utrecht.Octrooi verleend:Patent granted:Glen Andrew Oliver te Utrecht.Glen Andrew Oliver in Utrecht.16/04/201816/04/2018(45) Octrooischrift uitgegeven:(45) Patent issued:(74) Gemachtigde:(74) Agent:16/04/201816/04/2018ir. C.M. Jansen c.s. te Den Haag.ir. C.M. Jansen et al. In The Hague.

© Capsule, system and method for preparing a beverage © In a capsule containing a substance constituted by a mass of loose, solid particles, for the preparation of a potable beverage by extracting and/or dissolving the substance by means of supplying a fluid under pressure into the capsule, a screen, permeable to water and impermeable to a predominant portion of particles of the substance is positioned between the substance and the bottom. The screen is provided with a plurality of passages dimensioned so that at least a fraction of the substance can pass through the passages in solid form. A beverage brewing system comprising such a capsule and a method of use of such a capsule are described as well.© Capsule, system and method for preparing a beverage © In a capsule containing a substance constituted by a mass of loose, solid particles, for the preparation of a potable beverage by extracting and / or dissolving the substance by means of supplying a fluid under pressure into the capsule, a screen, permeable to water and impermeable to a predominant portion of particles of the substance is positioned between the substance and the bottom. The screen is provided with a variety of passages dimensioned so that at least a fraction of the substance can pass through the passages in solid form. A beverage brewing system including such a capsule and a method of use or such a capsule are described as well.

NL BI 2017586NL BI 2017586

Dit octrooi is verleend ongeacht het bijgevoegde resultaat van het onderzoek naar de stand van de techniek en schriftelijke opinie. Het octrooischrift komt overeen met de oorspronkelijk ingediende stukken.This patent has been granted regardless of the attached result of the research into the state of the art and written opinion. The patent corresponds to the documents originally submitted.

P112569NL00P112569NL00

TITLE: Capsule, system and method for preparing a beverageTITLE: Capsule, system and method for preparing a beverage

FIELD AND BACKGROUND OF THE INVENTIONFIELD AND BACKGROUND OF THE INVENTION

The invention relates to a capsule according to the introductory portion of claim 1. Such a capsule is known from European patent applicationThe invention relates to a capsule according to the introductory portion of claim 1. Such a capsule is known from European patent application

0 468 079.0 468 079.

In practice, such capsules are mostly arranged and used for extracting coffee, by pressing an injection fluid such as hot water under pressure through powder obtained by grinding roasted coffee beans. However, the substance, which may be in the form of for instance granules, chips or flakes, may also be constituted by or contain constituents that are to be dissolved and/or entrained, such as sugar or milk powder. Substances to be extracted may also be of other types than coffee, such as tea or herbs.In practice, such capsules are mostly arranged and used for extracting coffee, by pressing an injection fluid such as hot water under pressure through powder obtained by grinding roasted coffee beans. However, the substance, which may be in the form of for granules, chips or flakes, may also be constituted by or contain constituents that are dissolved and / or entrained, such as sugar or milk powder. Substances to be extracted may also be or other types than coffee, such as tea or herbs.

Widely used in the market are capsules of which the capsule body is of aluminium or plastic and of which the open end is sealed-off by a thin sheet, usually of aluminium. The closed end of the capsule body is typically referred to as the bottom. The coffee machine has a housing in which a major portion of the capsule body can be received and a closing member. The housing and/or the closing member is/are movable relative to the other between an operating position in which the flange of the capsule is clamped between the housing and a closing member and a transfer position leaving an opening through which a used capsule can be removed from the housing and a fresh capsule can be positioned in the housing. Piercing elements are provided which in use pierce a bottom portion of the capsule body inside the housing.Widely used in the market are capsules or which the capsule body is aluminum or plastic and which the open end is sealed-off by a thin sheet, usually or aluminum. The closed end of the capsule body is typically referred to as the bottom. The coffee machine has a housing in which a major portion of the capsule body can be received and a closing member. The housing and / or the closing member is / are movable relative to the other between an operating position in which the flange of the capsule is clamped between the housing and a closing member and a transfer position leaving an opening through which a used capsule can be removed from the housing and a fresh capsule can be positioned in the housing. Piercing elements are provided which in use pierce a bottom portion of the capsule body inside the housing.

When pressurised fluid is fed into the housing, it penetrates the capsule through the holes made by the piercing element, and causes an increase in the internal pressure which causes the cover to be torn, for instance with assistance of piercing members of the closing member. Then, a flow of water is pressed into the substance and brewed beverage exits the capsule and guided to a receptacle of the user outside of the machine. The cover may also be to some extent open prior to injection of the pressurized fluid, for instance if the capsule is packaged in a barrier material for retaining flavours, which barrier material is to be removed prior to use.When pressurized fluid is fed into the housing, it penetrates the capsule through the holes made by the piercing element, and causes an increase in the internal pressure which causes the cover to be, for instance with assistance or piercing members or the closing member. Then, a flow of water is pressed into the substance and brewed beverage exits the capsule and guided to a receptacle of the user outside of the machine. The cover may also be some open prior to injection of the pressurized fluid, for instance if the capsule is packaged in a barrier material for retaining flavors, which barrier material is removed prior to use.

European patent 1 165 398 discloses a capsule which comprises, in the dish of the capsule at the level of the bottom of the capsule, a means guaranteeing retention of solid substance when it is open, so that substance does not pass through the pierced openings while or after the piercing elements are retracted out of the capsule. This means may be a fabric which may be pierced easily by means of a perforating needle and, at the end of the extraction, its flexibility and elasticity allow the pierced openings to close again when said needle is removed from the cartridge so that the grounds do not exit the capsule. According to another solution a non-return valve is adhesively bonded to the bottom. This valve may have a cross-shaped cut-out which allows satisfactory opening and satisfactory re-closing when the extraction needle is inserted and removed.European patent 1 165 398 discloses a capsule which comprises, in the dish of the capsule at the level of the bottom of the capsule, a means guaranteeing retention of solid substance when it is open, so that substance does not pass through the pierced opening while or after the piercing elements are retracted out of the capsule. This means may be a fabric which may be pierced easily by means of a perforating needle and, at the end of the extraction, its flexibility and elasticity allow the pierced opening to close again when said needle is removed from the cartridge so that the grounds do not exit the capsule. According to another solution a non-return valve is adhesively bonded to the bottom. This valve may have a cross-shaped cut-out which allows satisfactory opening and satisfactory re-closing when the extraction needle is inserted and removed.

WO2010/115970 discloses a capsule with a filter downstream of the substance in the capsule, which filter has pyramid shaped openings that are dimensioned to prevent the powdered substance from passing through the openings.WO2010 / 115970 discloses a capsule with a filter downstream of the substance in the capsule, which filter has pyramid-shaped opening that are dimensioned to prevent the powdered substance from passing through the opening.

SUMMARY OF THE INVENTIONSUMMARY OF THE INVENTION

It is an object of the present invention to provide a capsule which can be manufactured in a simple manner at low costs and which is further improved with respect to processing of the substance into a beverage of high organoleptic and visual quality.It is an object of the present invention to provide a capsule which can be manufactured in a simple manner at low costs and which is further improved with respect to processing of the substance into a beverage or high organoleptic and visual quality.

According to the invention, this object is achieved by providing a capsule according to claim 1.According to the invention, this object has been achieved by providing a capsule according to claim 1.

Since the passages are dimensioned to allow particles of the substance to pass through in solid form, particles may pass to the outside of the capsule body after the piercing elements have been retracted and pressure from the outside is no longer applied to the capsule. Amounts of substance flowing out will show the user the substance from which the beverage has been brewed, which enhances the similarity to brewing coffee in a manually filled brewing apparatus such as a conventional espresso machine, so that the real coffee making experience is improved. Thus by doing exactly the opposite as proposed in the previously mentioned European patent 1 165 398, an important advantage is realised. Moreover a second advantage is realised. Because the screen is provided with a plurality of passages dimensioned so that at least a fraction of the substance can pass through in solid form, water distribution over the substance, through which the water is pressed, is guided effectively, but incurs less flow resistance than a screen of the same water permeable material without passages dimensioned so that at least a fraction of the substance can pass through in solid form. The relatively large passages provide distributed areas where flow resistance is particularly low. In particular the screen may be made from a filter material provided with the plurality of passages. More particularly the filter material may be a nonwoven material. It shows that such a screen provides an excellent water distribution over the substance bed (in particular ground coffee bed) so that extraction is improved. Without being bound to theory, it is expected that the improved extraction is obtained by a combination of the porosity of the filter material on the one hand and the passages in the filter material on the other hand.Since the passages are dimensioned to allow particles of the substance to pass through in solid form, particles may pass to the outside of the capsule body after the piercing elements have been retracted and pressure from the outside is no longer applied to the capsule. Amounts of substance flowing out will show the user the substance from which the beverage has been brewed, which enhances the similarity to brewing coffee in a manually filled brewing apparatus such as a conventional espresso machine, so that the real coffee making experience is improved. Thus by doing exactly the opposite as proposed in the previously mentioned European patent 1 165 398, an important advantage has been realized. Moreover, a second advantage has been realized. Because the screen is provided with a variety of passages dimensioned so that at least a fraction of the substance can pass through in solid form, water distribution over the substance, through which the water is pressed, is guided effectively, but incurs less flow resistance than a screen of the same water permeable material without passages dimensioned so that at least a fraction of the substance can pass through in solid form. The relatively large passages provide distributed areas where flow resistance is particularly low. In particular the screen may be made from a filter material provided with the various or passages. More particularly the filter material may be a non-woven material. It shows that such a screen provides an excellent water distribution over the substance bed (in particular ground coffee bed) so that extraction is improved. Without being bound to theory, it is expected that the improved extraction is obtained by a combination of the porosity of the filter material on the one hand and the passages in the filter material on the other hand.

The openings may for instance have a diameter of 1-4 mm. The diameter of the screen may for instance be 20-40 mm, for example 22-30 mm. The diameter of the bottom of the capsule may for instance be 20-40 mm, for example 22-30 mm. The diameter of the screen may be about the same as (e.g. 95 - 105% of) the diameter of the bottom at the inside of the capsule. The screen may for instance be provided with 4-30 passages, preferably about 1525 passages. The screen area including a pattern of the passages may cover 50100% of the bottom, the remainder of the screen area being free of a pattern of the passages. In a practical embodiment the screen is provided with 15-18 passages each having a diameter of 1.5-2.5 mm, preferably 1.6—2.2 mm, more preferably of 1.6-1.8 mm.The opening may for instance have a diameter of 1-4 mm. The diameter of the screen may be 20-40 mm for instance, 22-30 mm for example. The diameter of the bottom of the capsule may be 20-40 mm for instance, 22-30 mm for example. The diameter of the screen may be about the same as (e.g. 95 - 105% of) the diameter of the bottom at the inside of the capsule. The screen may be provided with 4-30 passages, preferably about 1525 passages. The screen area including a pattern of the passages may cover 50100% of the bottom, the remainder of the screen area being free of a pattern of the passages. In a practical embodiment the screen is provided with 15-18 passages each having a diameter of 1.5-2.5 mm, preferably 1.6 - 2.2 mm, more preferably or 1.6-1.8 mm.

The screen material may for instance have a weight of 20-200 g/cm², preferably 40-100 g/cm². The screen material may for instance have a thickness of 0.1-1 mm, preferably 0.2-0.5 mm. The screen material (without the passages) may for instance have an air permeability between 500 and 3000 l/(m²s) at a pressure drop of 100 Pa over the screen material, preferably between 1000 and 1500 l/(m²s) at a pressure drop of 100 Pa over the screen material.The screen material may have a weight of 20-200 g / cm² , preferably 40-100 g / cm² for instance. The screen material may have a thickness of 0.1-1 mm, preferably 0.2-0.5 mm, for instance. The screen material (without the passages) may have an air permeability between 500 and 3000 l / (m² s) at a pressure drop of 100 Pa over the screen material, preferably between 1000 and 1500 l / (m² s) at a pressure drop of 100 Pa over the screen material.

In general, as a result of the relatively low pressure loss at the screen, the screen according to the invention allows water to be distributed over flow paths including flow paths of a relatively great length, where pressure drop per unit of flow distance would otherwise be relatively low. Also any tendency of water to pass along flow paths circumventing the screen or to pass through a hole pierced in the screen is reduced because the pressure drop over the screen is lowered. Reducing the pressure drop over the screen further provides the advantage that more of the overall pressure drop is left as a net pressure drop over the substance, so that extraction can be more intensive.In general, as a result of the relatively low pressure loss on the screen, the screen according to the invention allows water to be distributed over flow paths including flow paths or a relatively great length, where pressure drop per unit or flow distance would otherwise be relatively low. Also any tendency or water to pass along flow paths circumventing the screen or to pass through a hole pierced in the screen is reduced because the pressure drop over the screen is lowered. Reducing the pressure drop over the screen further provides the advantage that more of the overall pressure drop is left as a net pressure drop over the substance, so that extraction can be more intensive.

Particular elaborations and embodiments of the invention are set forth in the dependent claims. The invention may also be embodied in a system according to claim 23 and in a method for brewing a beverage according to claim 25.Particular elaborations and the invention are set forth in the dependent claims. The invention may also be embodied in a system according to claim 23 and in a method for brewing a beverage according to claim 25.

Further features, effects and details of the invention appear from the detailed description and the drawings.Further features, effects and details of the invention appear from the detailed description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGSLETTER DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective cross-sectional view of a first example of a capsule according to the invention;FIG. 1 is a perspective cross-sectional view or a first example or a capsule according to the invention;

Fig. 2 is a schematic cross-sectional side view of the capsule according to Fig. 1 positioned between a housing and a closing member of a coffee making machine;FIG. 2 is a schematic cross-sectional side view of the capsule according to FIG. 1 positioned between a housing and a closing member of a coffee making machine;

Fig. 3 is a perspective cross-sectional view of a second example of a capsule according to the invention;FIG. 3 is a perspective cross-sectional view or a second example or a capsule according to the invention;

Fig. 4 is a top plan view of a screen of a third example of a capsule according to the invention;FIG. 4 is a top plan view or a screen or a third example or a capsule according to the invention;

Fig. 5 is a top plan view of a screen of a fourth example of a capsule according to the invention; andFIG. 5 is a top plan view or a screen or a fourth example or a capsule according to the invention; and

Fig. 6 is a top plan view of a screen of a fifth example of a capsule according to the invention.FIG. 6 is a top plan view or a screen or a fifth example or a capsule according to the invention.

DETAILED DESCRIPTIONDETAILED DESCRIPTION

In Figs. 1 and 2 a first example of a capsule 1 according to the invention is shown. The capsule 1 has a capsule body 2 having a bottom 3, a side wall 4, an end 5 opposite of the bottom 3 and a flange 6 extending outwardly from the side wall 4 and around the open end 5. A cover 7 of the capsule is attached to the outwardly extending flange 6 and hermetically closes off the end 5 of the capsule body 5 opposite of the bottom 3. For illustrative purposes, the cover 7 is shown as a transparent member. The cover may also be open to some extent, for instance in an embodiment in which the capsule is packaged in a flavour retaining barrier that is to be removed prior to use and in which the cover does not have to be opened further to allow the brewed beverage to flow through.In FIGs. 1 and 2 a first example of a capsule 1 according to the invention is shown. The capsule 1 has a capsule body 2 having a bottom 3, a side wall 4, an end 5 opposite of the bottom 3 and a flange 6 extending outwardly from the side wall 4 and around the open end 5. A cover 7 of the capsule is attached to the outwardly extending flange 6 and hermetically closed 5 of the capsule body 5 opposite of the bottom 3. For illustrative purposes, the cover 7 is shown as a transparent member. The cover may also be open to some extent, for instance in an embodiment in which the capsule is packaged in a flavor retaining barrier that has been removed prior to use and in which the cover does not have been opened further to allow the brewed beverage to flow through.

The capsule body 2 and the cover 7 bound a capsule chamber 8. The capsule chamber 8 contains a substance 9 constituted by a mass of loose, solid particles, for the preparation of a potable beverage by extracting and/or dissolving the substance by means of supplying an injection fluid under pressure into the capsule.The capsule body 2 and the cover 7 bound a capsule chamber 8. The capsule chamber 8 contains a substance 9 constituted by a mass of loose, solid particles, for the preparation of a potable beverage by extracting and / or dissolving the substance by means of supplying an injection fluid under pressure into the capsule.

In this example and also in other embodiments of the invention, the substance can for instance be ground, roasted coffee beans, but may also be another substance from which constituents are to be extracted and/or which is to be dissolved and/or emulsified when pressurised injection liquid such as hot water is passed through, for instance tea, milk powder and/or sugar, or dried soup. The substance may for instance be 5 - 40 grams, preferably 5 - 30 grams, more preferably 5 - 14 grams of roasted and ground coffee.In this example and also in other embodiments of the invention, the substance can for instance be ground, roasted coffee beans, but may also be another substance from which constituents are extracted and / or which is dissolved and / or emulsified when pressurized injection liquid such as hot water has passed through, for instance tea, milk powder and / or sugar, or dried soup. The substance may for instance be 5 - 40 grams, preferably 5 - 30 grams, more preferably 5 - 14 grams or roasted and ground coffee.

For compatibility with widely used coffee machines, it is generally preferred that the capsule is in accordance with one or more of the following features, wherein dimensions are to be selected within these ranges depending on the type of coffee making machine in which the capsule is to be used:For compatibility with widely used coffee machines, it is generally preferred that the capsule is in accordance with one or more of the following features, dimensions are to be selected within these ranges depending on the type of coffee making machine in which the capsule is to be used:

• the outer diameter of the outwardly extending flange is approximately 37 - 45 mm, • the diameter of the bottom of the capsule is about 23 - 30 mm, • an inner edge of a curled outer edge of the outwardly extending flange has a radius about the central capsule body axis of at least 32 - 42 mm, • the curled outer edge of the outwardly extending flange has a largest dimension of about 1.2 — 1.6 mm, • the inner diameter of the free end of the side wall of the capsule body is about 29 - 35 mm, • the distance between the free end of the side wall of the capsule body and an outermost edge of the outwardly extending flange is about 3.5-5 mm, • a height of the capsule body is about 28 - 40 mm, • the capsule body is truncated, wherein preferably the side wall of the capsule body encloses an angle with a line transverse to the central capsule body axis of about 94 - 98°, • the bottom of the capsule body has a largest inner diameter of about 23 - 29 mm, • the bottom of the capsule body is truncated, preferably having a bottom height of about 4 - 7 mm and wherein the bottom further has a generally flat central portion opposite the cover having a diameter of about 8-11 mm, • the height of the sealing member portion to be contacted first by the free end of the enclosure member when the enclosure member is closed is at least about 0.1 mm, more preferably at least 0.2 mm and most preferably at least 0.8 mm and at most 3 mm, more preferably at most 2 mm and most preferably at most 1.2 mm.• the outer diameter of the outwardly extending flange is approximately 37 - 45 mm, • the diameter of the bottom of the capsule is about 23 - 30 mm, • an inner edge of a curled outer edge or the outwardly extending flange has a radius about the central capsule body axis or at least 32 - 42 mm, • the curled outer edge of the outwardly extending flange has a largest dimension of about 1.2 - 1.6 mm, • the inner diameter of the free end of the side wall of the capsule body is about 29 - 35 mm, • the distance between the free end of the side wall of the capsule body and an outermost edge of the outwardly extending flange is about 3.5-5 mm, • a height of the capsule body is about 28 - 40 mm, • the capsule body is truncated, preferably the side wall of the capsule body encloses an angle with a line transverse to the central capsule body axis or about 94 - 98 °, • the bottom of the capsule body has a largest inner diameter or about 23 - 29 mm, • the bottom of the capsule body is truncated, preferably having a bottom height of about 4 - 7 mm and having the bottom further has a generally flat central portion opposite the cover having a diameter of about 8-11 mm, • the height of the sealing member portion to be contacted first by the free end of the enclosure member when the enclosure member is closed is at least about 0.1 mm, more preferably at least 0.2 mm and most preferably at least 0.8 mm and at most 3 mm, more preferably at most 2 mm and most preferably at most 1.2 mm.

The wall thickness of the cover (preferably made of aluminium) is preferably smaller than the wall thickness of the capsule body, which may for instance be of aluminium or plastic material, such that the cover can be caused to open with assistance of a pressure applied to the capsule chamber, for instance by causing the aluminium cover to tear open on a closing member of the beverage preparation device, such as an extraction plate of the beverage preparation device, under the influence of fluid pressure in the capsule.The wall thickness of the cover (preferably made of aluminum) is preferably narrower than the wall thickness of the capsule body, which may be for instance or aluminum or plastic material, such that the cover can be caused to be open with assistance or a pressure applied to the capsule chamber, for instance by causing the aluminum cover to open a closing member of the beverage preparation device, such as an extraction plate or the beverage preparation device, under the influence of fluid pressure in the capsule.

In the capsule chamber 8, a screen 10, of a material permeable to water and impermeable to a predominant portion of the particles of the substance 9 is arranged. The screen 10 is positioned between the substance 9 and the bottom 3 of the capsule and has a centre approximately coaxial with a centre line 11 of the capsule 1. In this example, the screen 10 is attached to the capsule body 1 along attachment zones 12 spaced from the centre 11 and circumferentially spaced from each other. The screen 10 may also be arranged loosely in the capsule, without being attached to the capsule body 2.In the capsule chamber 8, a screen 10, or a material permeable to water and impermeable to a predominant portion of the particles of the substance 9 is arranged. The screen 10 is positioned between the substance 9 and the bottom 3 of the capsule and has a center approximately coaxial with a center line 11 of the capsule 1. In this example, the screen 10 is attached to the capsule body 1 along attachment zones 12 spaced from the center 11 and circumferentially spaced from each other. The screen 10 may also be loosely arranged in the capsule, without being attached to the capsule body 2.

The circumferentially distributed attachment zones 12 keep a peripheral portion of the screen 10 in position in the capsule 1, yet interfere relatively little with liquid flow through the screen 10, so that a relatively large portion of the screen 10 up to its peripheral edge is available for liquid to pass through. Also, the screen 10 reliably keeps the piercing elements 13 (Fig. 2) separated from the substance, since a portion of the screen 10 centrally of the attachment zones 12 is left free to move away from the bottom 3 when the piercing elements 13 enter the capsule chamber 8 through perforations pierced thereby in the bottom 3 of the capsule body 2. It may however also be provided that the piercing elements do pierce the screen or that a passage is provided in the screen through which a tip end of the piercing element passes when it is pierced into the capsule.The circumferentially distributed attachment zones 12 keep a peripheral portion of the screen 10 in position in the capsule 1, yet interfere relatively little with liquid flow through the screen 10, so that a relatively large portion of the screen 10 up to its peripheral edge is available for liquid to pass through. Also, the screen 10 reliably keeps the piercing elements 13 (Fig. 2) separated from the substance, since a portion of the screen 10 centrally of the attachment zones 12 is left free to move away from the bottom 3 when the piercing elements 13 enter the capsule chamber 8 through perforations pierced in the bottom 3 of the capsule body 2. It may also be provided that the piercing elements do pierce the screen or that a passage is provided in the screen through which a tip end of the piercing element passes when it is pierced into the capsule.

The screen 10 is provided with a plurality of passages 23 dimensioned so that at least a fraction of the substance 9 can pass through the passages 23 in solid form. The fraction of the substance 9 that can pass (i.e. is small enough to pass) through the passages may for instance be the smallest 10%, 30% or 50% of the substance 9. It may also be provided that all particles of the substance are in principle capable of passing through the passages or that some of the passages allow a larger fraction of the substance to pass through than other ones of the passages. Also, even though particles are in principle capable of passing through the passages, in practice most of the substance, and also most of the fraction that can pass through the passages, will in fact not pass through the passages. This is because, after brewing, most of the substance is not exposed to backflow of sufficient magnitude to entrain these particles through the passages and because particles tend to cling to each other after having been wetted. However, it has been found that a significant amount of particles does pass through the passages and even to the outside of the capsule, so that after brewing a sample of the substance from which the beverage is brewed is visible and can easily be smelled by the consumer.The screen 10 is provided with a variety of passages 23 dimensioned so that at least a fraction of the substance 9 can pass through the passages 23 in solid form. The fraction of the substance 9 that can pass through the passages may for instance be the smallest 10%, 30% or 50% of the substance 9. It may also be provided that all particles of the substance are in principle capable of passing through the passages or that some of the passages allow a larger fraction of the substance to pass through than other ones of the passages. Also, even though particles are in principle capable of passing through the passages, in practice most of the substance, and also most of the fraction that can pass through the passages, will in fact not pass through the passages. This is because, after brewing, most of the substance is not exposed to backflow or sufficient magnitude to entrain these particles through the passages and because particles tend to cling to each other after having been legalized. However, it has been found that a significant amount of particles does pass through the passages and even to the outside of the capsule, so that after brewing a sample of the substance from which the beverage is brewed is visible and can easily be melted by the consumer.

Moreover, these passages 23 allow water distribution over the substance 9, through which the water is pressed with a smaller pressure drop over the screen, because the relatively large passages provide distributed local areas where flow resistance is particularly low. This allows water to be distributed over flow paths including flow paths of a relatively great length, where pressure drop per unit of flow distance would otherwise be relatively low. Also any tendency of water to pass along flow paths circumventing the screen 10 or to pass to a relatively large extent through a hole pierced in the screen is reduced, because the pressure drop over the screen 10 is lowered. Reducing the pressure drop over the screen 10 further provides the advantage that more of the overall pressure drop is left as a net pressure drop over the substance 9, so that extraction can be more intensive.Moreover, these passages 23 allow water distribution over the substance 9, through which the water is pressed with a smaller pressure drop over the screen, because the relatively large passages provide distributed local areas where flow resistance is particularly low. This allows water to be distributed over flow paths including flow paths or a relatively great length, where pressure drop per unit or flow distance would otherwise be relatively low. Also any tendency or water to pass along flow paths circumventing the screen 10 or to pass a relatively large extent through a hole pierced in the screen is reduced, because the pressure drop over the screen 10 is lowered. Reducing the pressure drop over the screen 10 further provides the advantage that more of the overall pressure drop is left as a net pressure drop over the substance 9, so that extraction can be more intensive.

For leaving a large peripheral portion of the screen 10 free for the liquid to pass through spacings in circumferential sense between successive attachment zones 12 preferably leave open at least 30% or, in order of increasing preference, 40%, 50%, 60% or 70% of a circumferential zone in which the attachment zones 12 are located.For leaving a large peripheral portion of the screen 10 free for the liquid to pass through spacings in circumferential sense between successive attachment zones 12 preferably leave open at least 30% or, in order or increasing preference, 40%, 50%, 60% or 70% of a circumferential zone in which the attachment zones are 12 located.

To allow the screen 10 to be displaced by the piercing elements 13 easily, without being pierced thereby, the screen 10 is preferably made of flexible material, such as paper, plastic film, or fibre material in the form of a woven, non-woven or knitted structure. Good brewing results at low costs can be achieved if the screen 10 is of filter paper. If the filter paper contains thermoplastic constituents such as fibres and/or binder material, these can be used for sealing to the capsule body in the attachment zones, as will be described in more detail.To allow the screen 10 to be displaced by the piercing elements 13 easily, without being pierced, the screen 10 is preferably made of flexible material, such as paper, plastic film, or fiber material in the form of a woven, non-woven or knitted structure. Good brewing results at low costs can be achieved if the screen is 10 or filter paper. If the filter paper contains thermoplastic constituents such as fibers and / or binder material, these can be used for sealing the capsule body in the attachment zones, as will be described in more detail.

For allowing the screen 10 to be displaced by the piercing elements 13 easily, it is also advantageous if all the attachment zones are distributed along a periphery of the screen element only.For allowing the screen 10 to be displaced by the piercing elements 13 easily, it is also advantageous if all the attachment zones are distributed along a periphery or the screen element only.

In Fig. 2 also relevant parts of a coffee machine, which, together with the capsule 1, form a beverage brewing system, are shown. These parts include a housing 14 in which a major portion of capsule body 2 can be received and a closing member 15 with passages 17 for allowing a prepared beverage to flow away from the capsule 1. The housing 14 and/or the closing member 15 is/are movable relative to the other between an operating position in which the flange 6 of the capsule 1 is clamped between the housing 14 and the closing member 15 and a transfer position leaving an opening through which a used capsule 1 can be removed from the housing 14 and a fresh capsule 1 can be positioned in the housing 14. The piercing elements 13, which are arranged for, in use, piercing a bottom portion 3 of the capsule body 2 inside the housing 14 in several piercing locations 16 (in principle a single piercing element for piercing in a single location would be possible as well; in this example three piercing elements are provided which lay on a circle such that each of the piercing elements pierces the capsule just outside a central part of the bottom).In FIG. 2 also relevant parts of a coffee machine, which, together with the capsule 1, form a beverage brewing system, are shown. These parts include a housing 14 in which a major portion or capsule body 2 can be received and a closing member 15 with passages 17 for allowing a prepared beverage to flow away from the capsule 1. The housing 14 and / or the closing member 15 is / are movable relative to the other between an operating position in which the flange 6 of the capsule 1 is clamped between the housing 14 and the closing member 15 and a transfer position leaving an opening through which a used capsule 1 can be removed from the housing 14 and a fresh capsule 1 can be positioned in the housing 14. The piercing elements 13, which are arranged for, in use, piercing a bottom portion 3 of the capsule body 2 inside the housing 14 in several piercing locations 16 (in principle a single piercing element for piercing in a single location would be possible as well, in this example three piercing elements are provided which lay on a circle such that each of the piercing elements pierces the capsule just outside a central p art of the bottom).

Such coffee machines are commercially available and therefore not described in more detail.Such coffee machines are commercially available and therefore not described in more detail.

In operation, the capsule 1 is positioned in the housing 14 and clamped between the housing 14 and the closing member 15 with perforations 17 for allowing brewed beverage outputted through the cover 7 to flow away from the capsule 1. A bottom portion 3 of the capsule body 2 inside the housing 14 is pierced and pressurised injection fluid, such as hot water, is fed into the housing 14, causing the injection fluid to penetrate the capsule 1 through at least one hole 16 pierced in the bottom 3. The hole may also have been provided in the bottom prior to placing the capsule in the housing, e.g. during manufacturing.In operation, the capsule 1 is positioned in the housing 14 and clamped between the housing 14 and the closing member 15 with perforations 17 for allowing brewed beverage outputted through the cover 7 to flow away from the capsule 1. A bottom portion 3 of the capsule body 2 inside the housing 14 is pierced and pressurized injection fluid, such as hot water, is fed into the housing 14, causing the injection fluid to penetrate the capsule 1 through at least one hole 16 pierced in the bottom 3. The hole may also have been provided in the bottom prior to placing the capsule in the housing, eg during manufacturing.

Then, the cover 7 is caused to be torn, preferably under the influence of fluid pressure in the capsule 1 and a flow of the injection fluid is passed at least partially through the screen 10, into and through the substance and through the cover so that a brewed beverage exits the capsule; and the brewed beverage is guided to a receptacle.Then, the cover 7 is caused to be, preferably under the influence of fluid pressure in the capsule 1 and a flow of the injection fluid is passed at least partially through the screen 10, into and through the substance and through the cover so that a brewed beverage exits the capsule; and the brewed beverage is guided to a receptacle.

Since the passages 23 are dimensioned to allow particles of the substance 9 to pass through in solid form, an appreciable amount of the particles will pass to the outside of the capsule body 2 after the piercing elements 13 have been retracted and pressure is no longer applied to the capsule 2. Thus, the user can see and better smell some of the substance from which the beverage has been brewed, which enhances the similarity to and association with brewing coffee in a manually filled brewing apparatus such as a conventional espresso machine that has to be filled with ground coffee manually.Since the passages 23 are dimensioned to allow particles of the substance 9 to pass through in solid form, an appreciable amount of the particles will pass to the outside of the capsule body 2 after the piercing elements 13 have been retracted and pressure is no longer applied to the capsule 2. Thus, the user can see and better smell some of the substance from which the beverage has been brewed, which enhances the similarity to and association with brewing coffee in a manually filled brewing apparatus such as a conventional espresso machine that has to be filled with ground coffee manually.

For radial distribution of water, it is preferred that at least some of the passages 23 are located peripherally of the location or locations of the piercings 16 or of openings pre-fabricated in the bottom.For radial distribution of water, it is preferred that at least some of the passages 23 are located peripherally or the location or locations of the piercings 16 or or opening pre-fabricated in the bottom.

In the system according to the invention, the attachment zones 12 are located peripherally of the piercing location or piercing locations 16 only. Thus, it is ensured that the piercing elements contact the screen 10 in an area surrounded by and located centrally relative to the attachment zones 12, so that the screen 10 can on the one hand move along with the tips of the piercing elements 13 contacting the screen 10 while on the other hand being retained in place in several positions surrounding the piercing elements 13, so that substance 9 is reliably prevented from reaching piercing locations 16, by circumventing the screen 10 or by being entrained with a piercing element 13 as it is retracted.In the system according to the invention, the attachment zones 12 are located peripherally or the piercing location or piercing locations 16 only. Thus, it is ensured that the piercing elements contact the screen 10 in an area surrounded by and centrally located relative to the attachment zones 12, so that the screen 10 can move on with the hand of the piercing elements 13 contacting the screen 10 while on the other hand being retained in place in several positions surrounding the piercing elements 13, so that substance 9 is reliably prevented from reaching piercing locations 16, by circumventing the screen 10 or by being entrained with a piercing element 13 as it is retracted.

For this purpose, it is moreover preferred that the attachment zones 13 are all arranged at a distance from the centre 11 of more than 60% or, more preferably, more than 70% of the radial size of the screen 10 in a direction from the centre 11 to the respective attachment zone 13. Also for this purpose, and for ease of manufacturing, it is preferred that the number of attachment zones 12 is less than 25 and, more preferably, less than 20 or 15. Thus the screen is attached to the capsule only at the attachment zones which are spaced from the centre and circumferentially spaced from each other. The screen is not attached to a centre area of the bottom. The screen is arranged to move away from the centre area of the bottom under influence of fluid injected via openings in the bottom which openings are created by means of an apparatus wherein the capsule is positioned for brewing coffee and/or under influence of piercing elements by means of which, in use, openings are pierced in the bottom of the capsule for injecting fluid into the capsule.For this purpose, it is moreover preferred that the attachment zones 13 are all arranged at a distance from the center 11 or more than 60% or, more preferably, more than 70% of the radial size of the screen 10 in a direction from the center 11 to the respective attachment zone 13. Also for this purpose, and for ease of manufacturing, it is preferred that the number of attachment zones 12 is less than 25 and, more preferably, less than 20 or 15. Thus the screen is attached to the capsule only at the attachment zones which are spaced from the center and circumferentially spaced from each other. The screen is not attached to a center area of the bottom. The screen is arranged to move away from the center area of the bottom under the influence of fluid injected through opening in the bottom which opening is created by means of an apparatus in which the capsule is positioned for brewing coffee and / or under influence of piercing elements by means of which, in use, opening are pierced in the bottom of the capsule for injecting fluid into the capsule.

A particularly reliable fixation along the periphery of the screen 10 can be achieved if, as in the present example, the attachment zones 12 are located directly adjacent to a transition 20 from the bottom 3 to the side wall 4. For reliable fixation, it is moreover preferred that the number of attachment zones is at least three and, more preferably, at least four, five or six.A particularly reliable fixation along the periphery of the screen 10 can be achieved if, as in the present example, the attachment zones 12 are located directly adjacent to a transition 20 from the bottom 3 to the side wall 4. For reliable fixation, it is moreover preferred that the number of attachment zones is at least three and, more preferably, at least four, five or six.

In Fig. 3 a second example of a capsule 51 according to the invention is shown. In principle, only features of this capsule 51 that differ significantly from the capsule 1 shown in Figs. 1 and 2 are described. For illustrative purposes, the cover 57 in Fig. 3 is shown as a transparent member.In FIG. 3 a second example of a capsule 51 according to the invention is shown. In principle, only features of this capsule 51 that is significantly different from the capsule 1 shown in Figs. 1 and 2 are described. For illustrative purposes, the cover 57 in FIG. 3 is shown as a transparent member.

In this capsule 51, the attachment zones 62 are at least partially located in a transition 70 from the bottom 53 to the side wall 54. This allows the screen 60 to be attached further from the centre 61 of the capsule 51. In the present example, this is taken to an extreme by arranging the attachment zones 62 in end portions near the bottom 53 of flutes 68 bulging outwardly of the general conical shape of the sidewall 54.In this capsule 51, the attachment zones 62 are at least partially located in a transition 70 from the bottom 53 to the side wall 54. This allows the screen 60 to be attached further from the center 61 of the capsule 51. In the present example , this is tasks to extreme by arranging the attachment zones 62 in end portions near the bottom 53 or flutes 68 bulging outwardly or the general conical shape of the sidewall 54.

In this example, the passages 73 through the screen 60 that are large enough to allow particles of the substance 59 to pass through in solid form are arranged in a single circle instead of in two concentric circles as the example shown in Figs 1 and 2.In this example, the passages 73 through the screen 60 that are large enough to allow particles of the substance 59 to pass through in solid form are arranged in a single circle instead of in two concentric circles as the example shown in Figs 1 and 2.

In Fig. 4 yet another example of a screen 110 for a capsule according to the invention is shown. In this example, the passages 123 are not of a circular shape, but of an elongate, triangular shape. By providing elongate passages, such a slots, oval passages or rhombus-shaped passages, water, relatively large areas of reduced resistance are provided, without proportionally allowing more of the substance to pass through. The attachment zones 112 are arranged in an annular zone outside of the annular zone in which the passages 123 are located. Thus, even if the position of the attachment zones 112 is fixed in rotational sense about the centre 126 of the screen 110, the screen can be attached to the capsule body in any position in rotational sense about that centre, because the attachment zones are always outside of the passages 123.In FIG. 4 yet another example of a screen 110 for a capsule according to the invention is shown. In this example, the passages 123 are not of a circular shape, but of an elongate, triangular shape. By providing elongate passages, such a slots, oval passages or rhombus-shaped passages, water, relatively large areas of reduced resistance are provided, without proportionally allowing more of the substance to pass through. The attachment zones 112 are arranged in an annular zone outside of the annular zone in which the passages are 123 located. Thus, even if the position of the attachment zones 112 is fixed in rotational sense about the center 126 or the screen 110, the screen can be attached to the capsule body in any position in rotational sense about that center, because the attachment zones are always outside of the passages 123.

In Fig. 5, a further example of a screen 160 for a capsule according to the invention is shown. In this example, the passages 173, 174, 175 are arranged in three annular zones concentric around the centre 176 of the screen 160. The passages 173, 174 in the inner rings are formed by openings in the material of the screen 160, which openings are circumferentially bounded by material of the screen 160. The passages 175 in the outer annular zone are formed by bays in the outer circumferential edge of the screen 160. The bays form areas of reduced flow resistance where water can pass between the perimeter of the screen 160 and the side wall of the capsule body.In FIG. 5, a further example of a screen 160 for a capsule according to the invention is shown. In this example, the passages 173, 174, 175 are arranged in three annular zones concentric around the center 176 of the screen 160. The passages 173, 174 in the inner rings are formed by opening in the material of the screen 160, which opening are circumferentially bound by material of the screen 160. The passages 175 in the outer annular zone are formed by bays in the outer circumferential edge of the screen 160. The bays form areas of reduced flow resistance where water can pass between the perimeter of the screen 160 and the side wall of the capsule body.

In Fig. 6, yet another example of a screen 210 for a capsule according to the invention is shown. In this example, the passages 223 (not all designated by a reference number) are arranged in a pattern that is uniform over the entire surface area of the screen 210. An advantage of passages arranged according to a uniform pattern is that the screen material can be provided with the passages very efficiently before screens are severed out of the screen material. Then the screens can be cut or otherwise severed out of the patterned screen material.In FIG. 6, yet another example of a screen 210 for a capsule according to the invention is shown. In this example, the passages 223 (not all designated by a reference number) are arranged in a pattern that is uniform over the entire surface area of the screen 210. An advantage of passages arranged according to a uniform pattern is that the screen material can be provided with the passages very efficiently before screens are severed out of the screen material. Then the screens can be cut or otherwise severed out of the patterned screen material.

In this example, the pattern is a uniform pattern of columns and rows at uniform mutual distances. However, also other patterns, such a patterns in which successive rows are mutually staggered in longitudinal direction, e.g. by half of the pitch between successive columns, or a pattern in which the passages are centred on corners of imaginary hexagonal cells.In this example, the pattern is a uniform pattern of columns and rows at uniform mutual distances. However, also other patterns, such patterns in which successive rows are mutually staggered in longitudinal direction, e.g. by half of the pitch between successive columns, or a pattern in which passages are centered on corners or imaginary hexagonal cells.

For effectively distributing water to radially outer portions of the capsule and of the substance 59, it is advantageous if at least some of the passages 73 are arranged at a distance from the centre of more than 40% and more preferably more than 50% or more than 60% of the distance of a peripheral edge from the centre, measured in a direction from the centre to the respective passage. Radially outward water distribution is even further enhanced if this applies to all of the passages.For effectively distributing water to radially outer portions of the capsule and of the substance 59, it is advantageous if at least some of the passages 73 are arranged at a distance from the center of more than 40% and more preferably more than 50% or more than 60% of the distance or a peripheral edge from the center, measured in a direction from the center to the respective passage. Radially outward water distribution is further enhanced if this applies to all of the passages.

Radially outward water distribution (which may also be achieved effectively using a screen with a uniform pattern of openings) is particularly relevant if, as for instance in the examples shown in Figs. 1-3. The capsule body 2, 52 has an internal cross-sectional area along a plane parallel to the cover 7, 57, which is larger at the cover 7, 57 than at the bottom 3, 53. In such a capsule 1, 51, the cross-sectional area increases from the bottom 3, 53 to the cover 7, 57, i.e. in the direction of flow of water through the substance, so that the water will need to distribute over a larger cross-sectional area as it flows through the substance 9, 59. By leading a relatively large portion of the water radially outwardly while incurring only a relatively small pressure loss at the screen, it is ensured that water is also effectively distributed to outer regions of cross-sections of the substance close to the cover 7, 57.Radially outward water distribution (which may also be achieved effectively using a screen with a uniform pattern or opening) is particularly relevant if, as for instance in the examples shown in Figs. 1-3. The capsule body 2, 52 has an internal cross-sectional area along a plane parallel to the cover 7, 57, which is larger at the cover 7, 57 than at the bottom 3, 53. In such a capsule 1, 51, the cross-sectional area increases from the bottom 3, 53 to the cover 7, 57, ie in the direction of flow of water through the substance, so that the water will need to distribute over a larger cross-sectional area as it flows through the substance 9, 59. By leading a relatively large portion of the water radially outwardly while incurring only a relatively small pressure loss on the screen, it is ensured that water is also effectively distributed to outer regions or cross-sections of the substance close to the cover 7, 57.

Radially outward water distribution is even more relevant if a shoulder is provided in a side wall of said capsule body, the internal cross-sectional area being larger at a cover side of the shoulder than at a bottom side of the shoulder.Radially outward water distribution is equally more relevant if a shoulder is provided in a side wall or said capsule body, the internal cross-sectional area being larger on a cover side of the shoulder than on a bottom side of the shoulder.

Particularly effective reductions of local flow resistance are achieved if at least some or all of the passages each have a cross-sectional surface area of at least 3 mm², for instance 3-7 mm², more preferably 4-5.5 mm² and/or a cross-sectional size of at least 1-4 mm. The cross-sectional size of the screen may for instance be 20-40 mm, for example 22-30 mm. The diameter of the bottom of the capsule may for instance be 20-40 mm, for example 22-30 mm. The diameter of the screen may be about the same as the diameter of the bottom at the inside of the capsule. The screen may for instance be provided with 4-30 passages, preferably about 15-25 passages. The screen area in which the passages are located may cover 50-100% of the bottom. In a practical embodiment the screen is provided with 15-18 passages each having a diameter of 1.5-2.5 mm, preferably 1.6—2.2 mm, more preferably of 1.6-1.8 mm.Particularly effective reductions or local flow resistance are achieved if at least some or all of the passages have a cross-sectional surface area or at least 3 mm² , for instance 3-7 mm² , more preferably 4-5.5 mm² and / or a cross-sectional size or at least 1-4 mm. The cross-sectional size of the screen may be 20-40 mm for instance, 22-30 mm for example. The diameter of the bottom of the capsule may be 20-40 mm for instance, 22-30 mm for example. The diameter of the screen may be about the same as the diameter of the bottom at the inside of the capsule. The screen may be provided with 4-30 passages, preferably about 15-25 passages. The screen area in which the passages are located may cover 50-100% of the bottom. In a practical embodiment the screen is provided with 15-18 passages each having a diameter of 1.5-2.5 mm, preferably 1.6 - 2.2 mm, more preferably or 1.6-1.8 mm.

The screen material may for instance have a specific weight of 20-200 g/cm², preferably 40-100 g/cm². The screen material may for instance have a thickness of 0.1-1 mm, preferably 0.2-0.5 mm. The screen material (without the passages) may for instance have an air permeability of 500 - 3000 l/(m²s) at a pressure drop of 100 Pa over the screen material, preferably between 1000 and 1500 l/(m²s) at a pressure drop of 100 Pa over the screen material.The screen material may have a specific weight of 20-200 g / cm² , preferably 40-100 g / cm² for instance. The screen material may have a thickness of 0.1-1 mm, preferably 0.2-0.5 mm, for instance. The screen material (without the passages) may have an air permeability of 500 - 3000 l / (m² s) at a pressure drop or 100 Pa over the screen material, preferably between 1000 and 1500 l / (m² s) at a pressure drop of 100 Pa over the screen material.

The screen has a surface area that can be regarded as being composed of an inner surface area and an outer surface area surrounding the inner surface area, the inner surface area forming at least 25% of a total surface area of the screen and an inner portion of the passages in the inner surface area provide an open surface area of a first proportion of the inner surface area, while an outer portion of the passages in the outer surface area provides an open surface area of a second proportion of the outer surface area. It is then advantageous for outward water distribution if the second proportion is larger than the first proportion. The inner surface area may for instance constitute at least 40%, 50% or 60% of the total surface area of the screen and the inner surface area may also be free of passages, at least prior to brewing. The inner surface area may have a circular boundary, a centre of the screen forming the centre of the inner surface area.The screen has a surface area that can be viewed as being composed of an inner surface area and an outer surface area surrounding the inner surface area, the inner surface area forming at least 25% of a total surface area or the screen and an inner portion whether the passages in the inner surface area provide an open surface area or a first proportion of the inner surface area, while an outer portion or the passages in the outer surface area provides an open surface area or a second proportion of the outer surface area. It is then advantageous for outward water distribution if the second proportion is larger than the first proportion. The inner surface area may be at least 40%, 50% or 60% of the total surface area or the screen and the inner surface area may also be free of passages, at least prior to brewing. The inner surface area may have a circular boundary, a center of the screen forming the center of the inner surface area.

The screen is preferably of water permeable material (e.g. one or more layers of fibrous material, such as filter paper, felt material or woven material), so that not all of the water flow is concentrated through the passages. However, if the number of passages is sufficiently large and the passages are sufficiently evenly distributed, the screen may also be of water impermeable material.The screen is preferably water permeable material (e.g. one or more layers of fibrous material, such as filter paper, felt material or woven material), so that not all of the water flow is concentrated through the passages. However, if the number of passages is sufficiently large and the passages are sufficiently equally distributed, the screen may also be water impermeable material.

Several features have been described as part of the same or separate embodiments. However, it will be appreciated that the scope of the invention also includes embodiments having combinations of all or some of these features other than the specific combinations of features embodied in the examples.Several features have been described as part of the same or separate expiry. However, it will be appreciated that the scope of the invention also includes combinations of all or some of these features other than the specific combinations or features embodied in the examples.